Laboratory Tests

Get Started. It's Free
or sign up with your email address
Laboratory Tests by Mind Map: Laboratory Tests

1. Hemolytic patterns on blood agar: degree of hemolyzing blood

1.1. Green: alpha hemolysis; partial breakdown of Hb

1.1.1. Streptococcus pneumoniae

1.1.2. Streptococci spp. (viridans)

1.2. Clear: beta hemolysis; total breakdown of Hb

1.2.1. Group A Streptococci

1.2.2. Group B Streptococci

1.2.3. Staphylococcus aureus

1.2.4. some Clostridia strains

1.2.5. 1/2 of Escherichia coli strains

1.3. Red: no hemolysis

2. Disc sensitivity testing

2.1. P-disc: optochin

2.1.1. P-disc sensitivity: does not grow in presence of P-disc

2.1.1.1. Streptococcus pneumoniae

2.1.2. P-disc insensitivity: grows in presence of P-disc

2.1.2.1. All other alpha hemolytic Streptococci spp.

2.2. A-disc: bacitracin

2.2.1. A-disc sensitivity: does not grow in presence of A-disc

2.2.1.1. Group A Streptococci (S. pyogenes)

2.2.2. A-disc insensitivity: grows in the presence of A-disc

2.2.2.1. All other beta hemolytic streptococci spp.

3. Lactose fermentation: MacConkey Agar

3.1. Red or purple agar: bacteria utilize lactose

3.1.1. E. coli

3.1.2. Klebsiella

3.2. pale or colorless agar: bacteria do not utilize lactose

3.2.1. Salmonella spp.

3.2.2. Shigella spp.

4. Oxidase

4.1. Oxidase (+): turns purple

4.1.1. Pseudomonas

4.1.2. Campylobacter

4.1.3. Helicobacter

4.1.4. Vibrio spp.

4.1.5. Neisseria

4.1.6. Pasteurella

4.2. Oxidase (-): does not change color

5. Catalase test: addition of dilute hydrogen peroxide

5.1. Catalase (+): bubbling

5.1.1. Staphylococcus spp.

5.2. Catalase (-): no bubbling

5.2.1. Streptococcus spp.

5.2.2. Enterococcus spp.

6. Coagulase test

6.1. Coagulase (+): clumping of plasma

6.1.1. Staphylococcus aureus

6.2. Coagulase (-): No clumping of plasma

6.2.1. Staphylococcus epidermidis

6.2.2. Staphylococcus saprophyticus

7. Sorbitol fermentation: MacConkey agar

7.1. no sorbitol fermentation

7.1.1. E. coli 0517/EHEC/STEC

7.2. sorbitol fermention

7.2.1. non EHEC strains of E. Coli